A new adaptive FEC loss control algorithm for voice over IP applications

Packet loss causes degradation in the quality of voice over IP (VOIP) applications. Forward error correction (FEC) methods which add redundant information to voice packets can be used to minimize the effects of packet loss. While these methods can reduce the effects of packet loss, they increase the amount of bandwidth used by a voice stream. This paper builds on existing work in adaptive FEC control algorithms to better control the amount of redundancy. The new adaptive FEC "USF algorithm" considers the history of packet losses in the network before changing the amount of redundancy and also does not react to burst losses. The performance of the USF algorithm is studied using a simulation model. The USF algorithm is able to maintain a loss rate one-half to one-third the loss rate maintained by the current algorithm for Internet traces and for network loss rates between 7% and 20% for synthetic traces.